McALLEN, Texas (Border Report) — Five U.S. citizens and a Mexican national who authorities say aided a drug cartel in Michoacan, Mexico, have been convicted of conspiring to possess 75 kilos of methamphetamine across the border in Laredo, Texas, Justice Department officials announced.

The group was convicted in Laredo after an investigation that began in February 2017, U.S. Attorney Alamdar Hamdani said.

Gerardo Martinez, 63, of Laredo, pleaded guilty on Thursday to leading a conspiracy to bring meth into the United States from Mexico and on to San Antonio, Dallas and beyond. Maria Valdez, 30, Rodrigo Sandoval, 31, and Karina Garcia, 26, all also of Laredo, previously pleaded guilty to their roles in the conspiracy, as did Mexican national Jose Alfredo Cruz-Salas, 37, and Ernesto Diaz-Velazquez, 40, Dallas, Hamdani said in a statement.

Martinez admitted to coordinating five drug trafficking events involving the distribution of meth through the border city of Laredo. He said he assisted by recruiting drivers who were willing to transport large quantities of high-purity meth through Laredo from Nuevo Laredo, Mexico.

Sandoval, Cruz-Salas, Valdez, Diaz-Velazquez and Garcia each previously pleaded guilty to conspiring to deliver and transport meth through Laredo while working for Martinez. Martinez maintained a front as an independent taxi driver while working on behalf of the La Familia Michoacana cartel.

The group is an independent drug cartel located in the southern Mexican state of Michoacan, Justice Department officials said.

Each defendant faces up to life in prison and a $10 million fine.